package com.kinglone.common.filter;

import java.util.regex.Pattern;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;

/** 
 * <code>{@link XssHttpServletRequestWrapper}</code> 
 * 
 * TODO : document me 
 * 
 * @author Administrator 
 */  
public class XssHttpServletRequestWrapper extends HttpServletRequestWrapper {  
    HttpServletRequest orgRequest = null;  
  
    public XssHttpServletRequestWrapper(HttpServletRequest request) {  
        super(request);  
        orgRequest = request;  
    }  
  
    /** 
    * 覆盖getParameter方法，将参数名和参数值都做xss过滤。<br/> 
    * 如果需要获得原始的值，则通过super.getParameterValues(name)来获取<br/> 
    * getParameterNames,getParameterValues和getParameterMap也可能需要覆盖 
    */  
    @Override  
    public String getParameter(String name) {  
        String value = super.getParameter(xssEncode(name));  
        if (value != null) {  
            value = xssEncode(value);  
        }  
        return value;  
    }  
  
    /** 
    * 覆盖getHeader方法，将参数名和参数值都做xss过滤。<br/> 
    * 如果需要获得原始的值，则通过super.getHeaders(name)来获取<br/> 
    * getHeaderNames 也可能需要覆盖 
    */  
    @Override  
    public String getHeader(String name) {  
  
        String value = super.getHeader(xssEncode(name));  
        if (value != null) {  
            value = xssEncode(value);  
        }  
        return value;  
    }  
  
    /** 
    * 将容易引起xss漏洞的半角字符直接替换成全角字符 
    * 
    * @param s 
    * @return 
    */  
    private static String xssEncode(String s) {  
        if (s == null || "".equals(s)) {  
            return s;  
        }  
        StringBuilder sb = new StringBuilder(s.length() + 16);  
        for (int i = 0; i < s.length(); i++) {  
            char c = s.charAt(i);  
            switch (c) {  
            case '>':  
                sb.append('＞');//全角大于号  
                break;  
            case '<':  
                sb.append('＜');//全角小于号  
                break;  
            case '\'':  
                sb.append('‘');//全角单引号  
                break;  
            case '\"':  
                sb.append('“');//全角双引号  
                break;  
            case '&':  
                sb.append('＆');//全角  
                break;  
            case '\\':  
                sb.append('＼');//全角斜线  
                break;  
            case '#':  
                sb.append('＃');//全角井号  
                break;  
            default:  
                sb.append(c);  
                break;  
            }  
        }  
        return sb.toString();  
    }  
  
    /** 
    * 获取最原始的request 
    * 
    * @return 
    */  
    public HttpServletRequest getOrgRequest() {  
        return orgRequest;  
    }  
  
    /** 
    * 获取最原始的request的静态方法 
    * 
    * @return 
    */  
    public static HttpServletRequest getOrgRequest(HttpServletRequest req) {  
        if (req instanceof XssHttpServletRequestWrapper) {  
            return ((XssHttpServletRequestWrapper) req).getOrgRequest();  
        }  
  
        return req;  
    }  
    
    /** 
     *  
     * 防止xss跨脚本攻击（替换，根据实际情况调整） 
     */  
  
    public static String stripXSSAndSql(String value) {  
        if (value != null) {  
            // NOTE: It's highly recommended to use the ESAPI library and  
            // uncomment the following line to  
            // avoid encoded attacks.  
            // value = ESAPI.encoder().canonicalize(value);  
            // Avoid null characters  
/**         value = value.replaceAll("", "");***/  
            // Avoid anything between script tags  
            Pattern scriptPattern = Pattern.compile("<[\r\n| | ]*script[\r\n| | ]*>(.*?)</[\r\n| | ]*script[\r\n| | ]*>", Pattern.CASE_INSENSITIVE);  
            value = scriptPattern.matcher(value).replaceAll("");  
            // Avoid anything in a src="http://www.yihaomen.com/article/java/..." type of e-xpression  
            scriptPattern = Pattern.compile("src[\r\n| | ]*=[\r\n| | ]*[\\\"|\\\'](.*?)[\\\"|\\\']", Pattern.CASE_INSENSITIVE | Pattern.MULTILINE | Pattern.DOTALL);  
            value = scriptPattern.matcher(value).replaceAll("");  
            // Remove any lonesome </script> tag  
            scriptPattern = Pattern.compile("</[\r\n| | ]*script[\r\n| | ]*>", Pattern.CASE_INSENSITIVE);  
            value = scriptPattern.matcher(value).replaceAll("");  
            // Remove any lonesome <script ...> tag  
            scriptPattern = Pattern.compile("<[\r\n| | ]*script(.*?)>", Pattern.CASE_INSENSITIVE | Pattern.MULTILINE | Pattern.DOTALL);  
            value = scriptPattern.matcher(value).replaceAll("");  
            // Avoid eval(...) expressions  
            scriptPattern = Pattern.compile("eval\\((.*?)\\)", Pattern.CASE_INSENSITIVE | Pattern.MULTILINE | Pattern.DOTALL);  
            value = scriptPattern.matcher(value).replaceAll("");  
            // Avoid e-xpression(...) expressions  
            scriptPattern = Pattern.compile("e-xpression\\((.*?)\\)", Pattern.CASE_INSENSITIVE | Pattern.MULTILINE | Pattern.DOTALL);  
            value = scriptPattern.matcher(value).replaceAll("");  
            // Avoid javascript:... expressions  
            scriptPattern = Pattern.compile("javascript[\r\n| | ]*:[\r\n| | ]*", Pattern.CASE_INSENSITIVE);  
            value = scriptPattern.matcher(value).replaceAll("");  
            // Avoid vbscript:... expressions  
            scriptPattern = Pattern.compile("vbscript[\r\n| | ]*:[\r\n| | ]*", Pattern.CASE_INSENSITIVE);  
            value = scriptPattern.matcher(value).replaceAll("");  
            // Avoid onload= expressions  
            scriptPattern = Pattern.compile("onload(.*?)=", Pattern.CASE_INSENSITIVE | Pattern.MULTILINE | Pattern.DOTALL);  
            value = scriptPattern.matcher(value).replaceAll("");  
        }  
        return value;  
    }  
  
}  